Such cutters have as a common feature a shank as the chucking part, which is inserted into the tool holder. Such cutters are used for example as slotting cutters or die-sinking cutters with a flat or round end. Such cutters are furthermore characterised in that they have a plurality of circumferential cutting edges in the region of their cutting section on the cutter ridges which are separated from each other by flutes, which cutting edges run in a helical manner and are in each case configured with a roughing profile in such a manner that the circumferential cutting edges are given chip-separating grooves, with the chip-separating grooves of cutter ridges which are adjacent in the circumferential direction being axially offset with respect to each other.
Such roughing profiles are standardised in “round” and “flat” versions for example in DIN 1836, with a differentiation being made between “extra coarse”, “coarse” and “fine” with regard to the structure of the profile, where applicable with regard to the pitch with which the chip-separating grooves are introduced into the cutter ridges. The profile structure such as also these pitches of the recesses which form the chip-separating grooves, depends on the tool, with the pitch being selected to be finer with increasing hardness of the material to be machined. The pitch can furthermore be dependent on the tool diameter, with it being the case here that the smaller the diameter of the shank cutter, the finer the pitch.
In contrast to finishing cutters, which usually have no profiling of the cutting edge or face, the interrupted, that is, profiled profile of the tool cutting edge of the roughing cutter allows a more rapid breaking of the chip. The roughing cutter is however generally not suitable for the production of a uniform surface with a high surface quality. Owing to the short-chipping behaviour of the removed material, however, much better chip removal is produced than with the finishing cutter. Owing to the high material removal rate, roughing tools of the type mentioned at the start are also very suitable for work in which it is a matter of removing material as effectively and quickly as possible to a finishing level of for example 0.5 mm before a work step with a finishing tool. Also, the cutting pressure and the power consumption of the machine are lower when working with such roughing cutters, and the tool can produce a high cutting depth and cutting width.
On the other hand, finishing cutters, that is, shank cutters with smooth cutting edges, can produce a workpiece surface with high dimensional accuracy and quality, that is, smoothness, which is produced owing to the regularity of the tool cutting edge, the high speed with at the same time low feed rate of the cutting tool and the generally low chip volume owing to the low finishing level, which can be between 0.1 and 1.0 mm depending on the application. If such finishing tools are however used with greater cutting depths or widths, chip removal problems occur owing to the longer and larger chips and also the power consumption and the cutting pressure increase over-proportionately. In order to reduce the tendency to vibrate which arises thereby, the cutting edge geometry has been changed—as described for example in the document DE 37 06 282 C2—by working with at least two unequal angles of twist in the region of the circumferential cutting edges, that is, the main cutter edges.
These unequal angles of twist mean that vibrations of the cutting tool can be minimised, which can be used to increase the service life or conversely to increase the feed rate values. Owing to the comparatively high power consumption and the high cutting pressure as well as the critical chip removal as before, this known finishing cutter can also only be operated at relatively small cutting widths.